Power control method and base station

ABSTRACT

An embodiment power control method includes obtaining, by a base station, a bit error rate (BER) of a physical uplink control channel (PUCCH) of a UE at a subframe i, and sending a transmit power control command δ′ PUCCH (i−k m ) having a value related to a transmit power control command obtained by the base station at a subframe i−k m  and that is determined according to the relationship of the BER to a bit error rate reference value. An embodiment base station includes a second obtaining unit configured to obtain a BER of a PUCCH of a UE at a subframe i and a second sending unit configured to send a transmit power control command δ′ PUCCH (i−k m ) having a value related to a transmit power control command obtained by the base station at a subframe i−k m  and that is determined according to the relationship of the BER to a bit error rate reference value.

This application is a continuation of U.S. patent application Ser. No.13/548,135, filed on Jul. 12, 2012, now U.S. Pat. No. 8,737,340, whichis a continuation of International Application No. PCT/CN2011/081902,filed on Nov. 8, 2011. The International Application claims priority toChinese Patent Application No. 201010561679.3, filed on Nov. 26, 2010.All the afore-mentioned patent applications are hereby incorporated byreference in their entireties.

TECHNICAL FIELD

The present invention relates to the field of communicationtechnologies, and in particular, to a power control method and a basestation.

BACKGROUND

A physical uplink control channel (PUCCH) of a long term evolution (LTE)technology uses a code division multiple access (CDMA) technology.Because the CDMA technology is a self-interference system, whenco-channel interference reaches a certain degree, a success rate ofdemodulating information carried by the PUCCH may be affected.Increasing PUCCH transmit power of a user terminal (UE, User Equipment)is a method for increasing the success rate of PUCCH demodulation.

For example, the PUCCH transmit power of the UE at a subframe i isindicated by PPUCCH(i), where PPUCCH(i)=min{PCMAX, P0_PUCCH+PL+h(nCQI,nHARQ)+ΔF_PUCCH(F)+g(i)}. The PCMAX is maximum transmit power of the UE.The P0_PUCCH is a received power level expected by a base station, andP0_PUCCH=P0_NOMINAL_PUCCH+P0_UE_PUCCH, where the P0_NOMINAL_PUCCHindicates a cell-specific received power level of the PUCCH expected bythe base station, and the P0_UE_PUCCH is a power offset value relativeto the P0_NOMINAL_PUCCH. The PL is a downlink path loss value estimatedby the UE. The h(nCQI, nHARQ) is a value decided by a PUCCH format,where nCQI is the number of information bits of a channel qualityindicator (CQI), and nHARQ is the number of information bits of an HARQ.The ΔF_PUCCH(F) is a power offset value of a different PUCCHtransmission format relative to a reference format (DCI FORMAT 1A). Theg(i) is a calibration value of inner loop power control, and is used tocompensate an error which is set for initial power of open loop powercontrol, and, where the is a transmit power control command (TransmitPower Control command, TPC command) on a subframe.

In the prior art, after receiving the P0_NOMINAL_PUCCH, P0_UE_PUCCH,and, the UE may calculate the PUCCH transmit power at the subframe i byusing the foregoing formula, but the PUCCH transmit power at thesubframe i calculated by the UE is inaccurate, and thus an effect ofsuppressing network interference caused by increasing the PUCCH transmitpower is not good.

SUMMARY OF THE INVENTION

According to one aspect, the present invention provides a power controlmethod. The method includes obtaining, by a base station, INPUCCH(i),where the INPUCCH(i) is average interference noise power of a physicaluplink control channel (PUCCH) carried by radio resources that areallocated by the base station at a subframe i. The method furtherincludes sending, by the base station, a parameter P0_NOMINAL_PUCCH(i)for power control at the subframe i. If a relative difference betweenthe INPUCCH(i) and a power reference value INPUCCH_REF is greater than athreshold INTH_PUCCH, a value of the P0_NOMINAL_PUCCH(i) is a sum ofSINR0_NOMINAL_PUCCH and INPUCCH at the subframe i, where theSINR0_NOMINAL_PUCCH is a first signal to interference plus noise ratioof the PUCCH obtained by the base station according to a lowest-classservice used by a UE located at a cell edge and a first uplink controlinformation format; otherwise, the value of the P0_NOMINAL_PUCCH(i) isthe same as a value of a parameter P0_NOMINAL_PUCCH(i−1) for the powercontrol at a subframe i−1.

According to another aspect, the present invention provides a powercontrol method. The method includes obtaining, by a base station, a biterror rate BER(i) of a physical uplink control channel (PUCCH) of a userequipment (UE) at a subframe i; and sending, by the base station, atransmit power control command, where a value of ranges from 0 to M−1, Mis an integer greater than 1, and a value of the is any one of thefollowing. If the BER(i) is greater than a bit error rate referencevalue BERPUCCH_REF where the ΔSINRUE_QCI(i) is a first signal tointerference plus noise ratio offset used by the UE at the subframe i.Alternatively, if the BER(i) is smaller than the BERPUCCH_REF where theΔSINROFFSET(i) is a second signal to interference plus noise ratiooffset used by the UE at the subframe i. Alternatively, if the BER(i) isequal to the BERPUCCH_REF, the value of the is the same as a value ofthe, where the is a transmit power control command obtained by the basestation at a subframe i−km.

According to another aspect, the present invention provides a basestation including a first obtaining unit configured to obtainINPUCCH(i). The INPUCCH(i) is average interference noise power of aphysical uplink control channel (PUCCH) carried by radio resources thatare allocated by the base station at a subframe i. A first sending unitis configured to send a parameter P0_NOMINAL_PUCCH(i) for power controlat the subframe i. If a relative difference between the INPUCCH(i) and apower reference value INPUCCH_REF is greater than a thresholdINTH_PUCCH, a value of the P0_NOMINAL_PUCCH(i) is a sum ofSINR0_NOMINAL_PUCCH and INPUCCH at the subframe i, where theSINR0_NOMINAL_PUCCH is a first signal to interference plus noise ratioof the PUCCH obtained by the first obtaining unit according to alowest-class service used by a UE located at a cell edge and a firstuplink control information format; otherwise, the value of theP0_NOMINAL_PUCCH(i) is the same as a value of a parameterP0_NOMINAL_PUCCH(i−1) for the power control at a subframe i−1.

According to another aspect, the present invention provides a basestation including a second obtaining unit configured to obtain a biterror rate BER(i) of a physical uplink control channel (PUCCH) of a userequipment (UE) at a subframe i. A second sending unit, configured tosend a transmit power control command, where a value of m ranges from 0to M−1, M is an integer greater than 1, and a value of the is any one ofthe following. If the BER(i) is greater than a bit error rate referencevalue BERPUCCH_REF where the ΔSINRUE_QCI(i) is a first signal tointerference plus noise ratio offset used by the UE at the subframe i.Alternatively, if the BER(i) is smaller than the BERPUCCH_REF where theΔSINROFFSET(i) is a second signal to interference plus noise ratiooffset used by the UE at the subframe i. Alternatively, if the BER(i) isequal to the BERPUCCH_REF, the value of the is the same as a value ofthe, where the is a transmit power control command obtained by thesecond obtaining unit at a subframe i−km.

In the embodiments of the present invention, the base station may send amore accurate parameter to the UE, so that PUCCH transmit powercalculated by the UE at the subframe i is more accurate, and networkinterference caused by increasing the PUCCH transmit power is furtherreduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic flowchart of a power control method according toan embodiment of the present invention;

FIG. 2 is a schematic flowchart of a power control method according toanother embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a base station according toanother embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a base station according toanother embodiment of the present invention; and

FIG. 5 is a schematic structural diagram of a base station according toanother embodiment of the present invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The technical solutions in the embodiments of the present invention arehereinafter described clearly and completely with reference to theaccompanying drawings in the embodiments of the present invention.Obviously, the described embodiments are only part of the embodiments ofthe present invention, rather than all of the embodiments of the presentinvention. All other embodiments derived by persons of ordinary skill inthe art based on the embodiments of the present invention without makingcreative efforts shall fall within the scope of the present invention.

In the embodiments of the present invention, i is placed in brackets andused as a part of a parameter X, namely, in the form of X(i), indicatinga case when the parameter X is at a subframe i. For example, P_(PUCCH)indicates PUCCH transmit power of a UE, and P_(PUCCH)(i) indicates thePUCCH transmit power of the UE at the subframe i. A base station in theembodiments of the present invention may be any access network devicefor controlling power of the UE, for example, an evolved NodeB (eNB,evolved Node base station) in an LTE system or LTE-Advance system.

Referring to FIG. 1, an embodiment of the present invention provides apower control method. In this embodiment, a base station may send aparameter related to a P_(PUCCH)(i) of a UE to the UE in a cell undercontrol of the base station, for example, P₀ _(—) _(NOMINAL) _(—)_(PUCCH) and P_(O) _(—) _(UE) _(—) _(PUCCH). As compared with the priorart, the P₀ _(—) _(NOMINAL) _(—) _(PUCCH) sent by the base station tothe UE is more accurate. Therefore, the UE obtains accurate P₀ _(—)_(PUCCH) according to the accurate P_(O) _(—) _(NOMINAL) _(—) _(PUCCH),so that the finally obtained P_(PUCCH)(i) is more accurate. Thisembodiment may include the following steps.

101. A base station determines a lowest-class service used by a UElocated at a cell edge and an uplink control information format(hereinafter referred to as a first uplink control information format)of a PUCCH corresponding to the lowest-class service used by theforegoing UE.

The lowest-class service used by the UE located at the cell edge may beset according to a market need, for example, VoIP, an Internet access,or other services determined by a telecom operator. The first uplinkcontrol information format is set according to a control signaling typecarried on the PUCCH, and may be one of FORMAT 1a, FORMAT 1b, FORMAT 2,FORMAT 2a, and FORMAT 2b.

The base station may determine, according to a geographic location ofthe UE, whether the UE is located at the cell edge, or may determine,according to a radio channel condition, whether the UE is located at thecell edge, for example, determine the UE whose radio channel conditiondeteriorates to a certain degree in a network as a UE located at thecell edge. For example, in mobile communication, a UE located at andunder 5% in a cumulative distribution function (CDF, CumulativeDistribution Function) curve is a UE located at the cell edge. If thereare multiple UEs located at the cell edge, the base station may obtainthe lowest-class service used by only one of the UEs and the firstuplink control information format. Optionally, the UE selected by thebase station is a UE at the lowest position in the CDF curve, that is, aUE with the worst channel condition.

102. The base station obtains a first signal to interference plus noiseratio SINR₀ _(—) _(NOMINAL) _(—) _(PUCCH) of the PUCCH according to thelowest-class service used by the UE located at the cell edge and thefirst uplink control information format.

The SINR₀ _(—) _(NOMINAL) _(—) _(PUCCH) is a signal to interference plusnoise ratio that the base station expects the PUCCH, which uses thefirst uplink control information format, to reach in order to ensurequality of service of the lowest-class service used by the UE, and itsunit may be dB. Those skilled in the art may understand that a serviceclass may be indicated by a quality of service class identifier (QoSclass identifier, QCI).

In this embodiment, the base station may generate the SINR₀ _(—)_(NOMINAL) _(—) _(PUCCH) according to the lowest-class service and firstuplink control information format, so that the generated SINR₀ _(—)_(NOMINAL) _(—) _(PUCCH) corresponding to the foregoing lowest-classservice satisfies a demodulation threshold requirement for demodulatingfeedback information (such as ACK or NACK) carried on the PUCCH of thefirst uplink control information format. Those skilled in the art mayunderstand that different scenarios and/or different channel conditionsaffect a demodulation success rate, and that the correspondingdemodulation threshold requirement may also be different. For example, avalue of a demodulation threshold may be any one of 10 dB to 30 dB.

Optionally, if the base station periodically sends a parameter relatedto the P_(PUCCH)(i) of the UE to the UE, that is, the UE updates theP_(PUCCH)(i) according to an update period, the base station only needsto finish obtaining the first signal to interference plus noise ratio ata certain time before the next update period arrives.

103. The base station obtains IN_(PUCCH)(i), namely, averageinterference noise power of a PUCCH carried by radio resources (RB,Radio Bearer) at a subframe i.

A unit of the IN_(PUCCH)(i) may be dBm.

In this step, the RBs carrying the PUCCH include RBs carrying the PUCCHof the current uplink control information format.

104. The base station judges whether a relative difference between theIN_(PUCCH)(i) and a power reference value IN_(PUCCH) _(—) _(REF) isgreater than a threshold IN_(TH) _(—) _(PUCCH). If yes, step 105 isexecuted; if no, step 106 is executed.

A unit of the IN_(PUCCH) _(—) _(REF) and IN_(TH) _(—) _(PUCCH) may bedBm.

The power reference value IN_(PUCCH) _(—) _(REF) in this step may be apreset value of the base station, or may be a value determined by thebase station according to the average interference noise power of theRBs carrying a PUCCH at a certain subframe of the UE.

In this step, the base station may preset the threshold IN_(TH) _(—)_(PUCCH), or may perform test estimation under a channel condition so asto obtain the IN_(TH) _(—) _(PUCCH). Those skilled in the art mayunderstand that the value of the IN_(TH) _(—) _(PUCCH) obtained by thebase station may be different under different channel conditions. Forexample, the value of the IN_(TH) _(—) _(PUCCH) is any one of −121 dBmto −91 dBm. By adjusting the value of the IN_(TH) _(—) _(PUCCH), ananti-interference capability of the UE may be enhanced when interferencenoise of the cell increases to a certain degree (namely, greater than acertain threshold), so that performance of the UE can be better ensured.In addition, when the interference noise of the cell is reduced to acertain degree, transmit power of each UE under the base station can bereduced, so that interference on a neighboring cell is reduced while theperformance of the UE is ensured.

If |IN_(PUCCH)(i)−IN_(PUCCH) _(—) _(REF)|>IN_(TH) _(—) _(PUCCH), thebase station may learn that when an update period arrives, and if thecurrently measured IN_(PUCCH)(i) changes notably relative to thereference IN value, then the base station executes step 105 to adjust P₀_(—) _(NOMINAL) _(—) _(PUCCH)“∥” in this embodiment indicates anabsolute value.

If |IN_(PUCCH)(i)−IN_(PUCCH) _(—) _(REF)|≦IN_(TH) _(—) _(PUCCH), thebase station may learn that, relative to a subframe i−1, the cellinterference noise at the subframe i changes little, then the basestation executes step 106 and keeps the P₀ _(—) _(NOMINAL) _(—) _(PUCCH)unchanged. In this way, the performance of the UE does not deterioratein the case that the anti-interference capability of the UE does notchange, and an interference condition of the whole network does notchange.

105. The base station sends P₀ _(—) _(NOMINAL) _(—) _(PUCCH)(i) to theUE, namely, the parameter P₀ _(—) _(NOMINAL) _(—) _(PUCCH) of the UE atthe subframe i. P₀ _(—) _(NOMINAL) _(—) _(PUCCH)(i)=SINR₀ _(—)_(NOMINAL) _(—) _(PUCCH)+IN_(PUCCH)(i).

Optionally, the base station sends the P₀ _(—) _(NOMINAL) _(—)_(PUCCH)(i) to all UEs in the cell through a broadcast channel.

Optionally, the base station further updates the power reference valueIN_(PUCCH) _(—) _(REF) to the value of IN_(PUCCH)(i), that is, theupdated IN_(PUCCH) _(—) _(REF)=IN_(PUCCH)(i). Further, the updatedIN_(PUCCH) _(—) _(REF) will be used by the base station in the nextprocess of judging the PUCCH transmit power. For example, the basestation may execute step 104 within each update period of the PUCCHtransmit power. Assume that the base station changes the IN_(PUCCH) _(—)_(REF) used in the judging process to the value of IN_(PUCCH)(i) after aprevious judging process of step 104, the base station uses the changedIN_(PUCCH) _(—) _(REF) (namely, IN_(PUCCH) _(—) _(REF) with the valueIN_(PUCCH)(i)) as the current power reference value in a next judgingprocess of step 104.

If the value of the changed IN_(PUCCH) _(—) _(REF) greater thanIN_(PUCCH) _(—) _(REF) is before the change, the base station increasesthe IN_(PUCCH) _(—) _(REF) by using this method, which is helpful forincreasing the anti-interference capability of the UE at the nextIN_(PUCCH)(i) update period. If the value of the changed IN_(PUCCH) _(—)_(REF) is smaller than IN_(PUCCH) _(—) _(REF) before the change, thebase station decreases the IN_(PUCCH) _(—) _(REF) by using this method,which is helpful for reducing network interference at the nextIN_(PUCCH)(i) update period.

By updating IN_(PUCCH) _(—) _(REF), the base station may make moreaccurate judgment in the subsequent process of determining a value ofthe P₀ _(—) _(NOMINAL) _(—) _(PUCCH)(i), so that the UE can obtain moreaccurate PUCCH(i) according to a more accurate parameter.

106. The base station sends the P₀ _(—) _(NOMINAL) _(—) _(PUCCH)(i) tothe UE, where P₀ _(—) _(NOMINAL) _(—) _(PUCCH)(i)=P₀ _(—) _(NOMINAL)_(—) _(PUCCH)(i−1), that is, a value of the P₀ _(—) _(NOMINAL) _(—)_(PUCCH) at the subframe i is the same as a value of the P₀ _(—)_(NOMINAL) _(—) _(PUCCH) at the subframe i−1.

Optionally, the base station sends the P₀ _(—) _(NOMINAL) _(—)_(PUCCH)(i) to all UEs in the cell through the broadcast channel.

In this embodiment, when the relative difference between theIN_(PUCCH)(i) and the IN_(PUCCH) _(—) _(REF) is greater than thethreshold, the base station may determine the P₀ _(—) _(NOMINAL) _(—)_(PUCCH) according to the SINR₀ _(—) _(NOMINAL) _(—) _(PUCCH) andIN_(PUCCH)(i) and send the P₀ _(—) _(NOMINAL) _(—) _(PUCCH) to the UE.As compared with the prior art, the P_(O) _(—) _(NOMINAL) _(—)_(PUCCH)(i) is more accurate. Therefore, the P_(PUCCH)(i) obtained bythe UE is more accurate, and reliability of signaling transmission canbe ensured in the case that the PUCCH channel of each UE in the cellunder control of the base station is based on code divisionmultiplexing.

When this embodiment is applied in a scenario where the UE accesses acertain cell under control of the base station, the P_(PUCCH)(i)determined by the UE=min{P_(CMAX), P_(O) _(—) _(PUCCH)+PL+h(n_(CQI),n_(HARQ))+Δ_(F) _(—) _(PUCCH)(F)}. Therefore, the UE determines accurateP₀ _(—) _(PUCCH) according to the received accurate P₀ _(—) _(NOMINAL)_(—) _(PUCCH), and then performs accurate open loop power control of thePUCCH transmit power according to the foregoing formula.

Further, the PUCCH in this embodiment may carry the feedback information(signaling such as ACK and NACK), while the feedback information isrelevant to downlink data carried on a physical downlink shared channel(Physical Downlink Share Channel, PDSCH) corresponding to the PUCCH.Therefore, the base station may increase the PUCCH transmit power of theUE when the cell interference increases, thereby ensuring correctdecoding of the foregoing feedback information, and avoiding incorrectretransmission of the downlink data carried on the PDSCH. Because thebase station increases the PUCCH transmit power of the UE based on theSINR₀ _(—) _(NOMINAL) _(—) _(PUCCH) in the foregoing process, the basestation may maximally reduce the network interference while ensuringnormal use of the lowest-class service used by the UE, where the UE islocated at the cell edge, after increasing the PUCCH transmit power.

The difference between another embodiment of the present invention andthe foregoing embodiment is that step 102 is changed to be executedbetween step 104 and step 105, that is, the base station executes steps101, 103, and 104 sequentially, and then executes steps 102 and 105sequentially according to a judging result of step 104, or executes step106. The difference between another embodiment of the present inventionand the foregoing embodiment is that steps 101 and 102 are changed to beexecuted between step 104 and step 105, that is, the base stationexecutes steps 103 and 104 sequentially, and then executes steps 101,102, and 105 sequentially according to the judging result of step 104,or executes step 106. In the two embodiments, when the base stationjudges that the relative difference between the IN_(PUCCH)(i) and theIN_(PUCCH) _(—) _(REF) is not greater than the threshold, the step ofobtaining the IN_(PUCCH)(i) does not need to be executed, which may savepower of the base station.

Those skilled in the art may understand that the base station may sendthe P₀ _(—) _(NOMINAL) _(—) _(PUCCH) for the UE to obtain the P₀ _(—)_(PUCCH) regardless of an FDD system or a TDD system, therebyimplementing the open loop power control. Therefore, the foregoingembodiments are applicable to both the FDD system and the TDD system.

Referring to FIG. 2, another embodiment of the present inventionprovides a power control method. In this embodiment, a base station maysend a parameter related to the P_(PUCCH)(i) of an online UE to the UEin a cell under control of the base station, for example, P₀ _(—)_(NOMINAL) _(—) _(PUCCH), P_(O) _(—) _(UE) _(—) _(PUCCH), and δ_(PUCCH).According to the formula

${{g(i)} = {{g\left( {i - 1} \right)} + {\sum\limits_{m = 0}^{M - 1}{\delta_{PUCCH}\left( {i - k_{m}} \right)}}}},$

the UE obtains g(i). As compared with the prior art, the δ_(PUCCH) sentby the base station to the UE is more accurate. Therefore, the UEobtains the accurate g(i) according to the accurate δ_(PUCCH), so thatthe finally obtained P_(PUCCH)(i) is more accurate. This embodiment mayinclude the following steps.

201. A base station obtains a highest-class service used by a UE at atime i and an uplink control information format (hereinafter referred toas a second uplink control information format) of a PUCCH correspondingto the highest-class service used by the UE.

For example, the base station may use the prior art to obtain a terminalidentifier of any online UE, the highest-class service used by the UEand its corresponding uplink control information format of the PUCCH.The uplink control information format of the PUCCH may be any one ofPUCCH format 1a, PUCCH format 1b, PUCCH format 2, PUCCH format 2a, andPUCCH format 2b.

Optionally, the highest-class service used by the UE is a highest-classservice used by the UE at a certain time. For example, if the UE beginsto use a service at a certain time, while a class of the service ishigher than those of other services being used by the UE, the basestation may obtain the service and the uplink control information formatof the PUCCH corresponding to the service.

202. The base station obtains a second signal to interference plus noiseratio SINR_(O) _(—) _(UE) _(—) _(PUCCH) _(—) _(MAX)(i) of the PUCCHaccording to the highest-class service used by the UE at the time i andthe second uplink control information format.

The SINR_(O) _(—) _(UE) _(—) _(PUCCH) _(—) _(MAX) is a signal tointerference plus noise ratio that the base station expects the PUCCH,which uses the second uplink control information format, to reach inorder to ensure quality of service of the highest-class service used bythe UE, and its unit may be dB.

Optionally, if the base station periodically sends a parameter relatedto a P_(PUCCH)(i) of the UE to the UE, that is, the UE updates theP_(PUCCH)(i) according to an update period, the base station only needsto finish obtaining the second signal to interference plus noise ratioat a certain time before a next update period arrives.

In this embodiment, the base station may generate SINR_(O) _(—) _(UE)_(—) _(PUCCH) _(—) _(MAX) according to the highest-class service andsecond uplink control information format, so that the generated SINR₀_(—) _(UE) _(—) _(PUCCH) _(—) _(MAX) corresponding to the foregoinghighest-class service satisfies a demodulation threshold requirement fordemodulating feedback information (such as ACK or NACK) carried on thePUCCH of the second uplink control information format. Those skilled inthe art may understand that different scenarios and/or different channelconditions affect a demodulation success rate, and that thecorresponding demodulation threshold requirement may also be different.For example, the value of a demodulation threshold may be any one of 10dB to 30 dB.

203. The base station obtains a transmit power control commandδ_(PUCCH)(i−k_(m)) at a subframe i−k_(m), where a value of m ranges from0 to M−1 (M is an integer greater than 1).

In this step, the base station obtains M transmit power control commandsin total.

For example, in a frequency division duplex (FDD, Frequency DivisionDuplex) system, a value of k₀ may be 4, and a value of M may be 1. In atime division duplex (TDD, Time Division Duplex) system, reference maybe made to the following Table 1 for a downlink association set index(Downlink association set index) K formed of k_(m).

TABLE 1 Uplink- Downlink Subframe n Configuration 0 1 2 3 4 5 6 7 8 9 0— — 6 — 4 — — 6 — 4 1 — — 7, 6 4 — — — 7, 6 4 — 2 — — 8, 7, 4, 6 — — — —8, 7, 4, 6 — — 3 — — 7, 6, 11 6, 5 5, 4 — — — — — 4 — — 12, 8, 7, 11 6,5, 4, 7 — — — — — — 5 — — 13, 12, 9, 8, 7, 5, 4, 11, 6 — — — — — — — 6 —— 7 7 5 — — 7 7 —

204. The base station compares BER(i) with BER_(PUCCH) _(—) _(REF),where the BER(i) indicates a bit error rate at a subframe i, and theBER_(PUCCH) _(—) _(REF) is a bit error rate reference value. If theBER(i) is greater than the BER_(PUCCH) _(—) _(REF), step 205 isexecuted; if the BER (i) at the subframe i is smaller than theBER_(PUCCH) _(—) _(REF), step 206 is executed; if the BER (i) at thesubframe i is equal to the BER_(PUCCH) _(—) _(REF), step 207 isexecuted.

The BER(i) may be a bit error rate of the PUCCH obtained by the basestation according to the prior art when the UE is at the subframe i. TheBER(i) and BER_(PUCCH) _(—) _(REF) may be percentages.

In this step, the base station may preset the BER_(PUCCH) _(—) _(REF),or may perform test estimation under a channel condition so as to obtainthe BER_(PUCCH) _(—) _(REF). For example, the base station sets theBER_(PUCCH) _(—) _(REF) according to the demodulation success rate offeedback data carried on the PUCCH, where a service of a physicaldownlink shared channel (PDSCH) corresponding to the foregoing feedbackdata is the highest-class service. Those skilled in the art mayunderstand that different scenarios and/or different channel conditionsaffect the demodulation success rate, and that a value of theBER_(PUCCH) _(—) _(REF) obtained by the base station may be different.For example, the value of the BER_(PUCCH) _(—) _(RE) is any one of 0.1%to 15%.

If BER(i)>BER(i)>BER_(PUCCH) _(—) _(REF), the base station may learnthat PUCCH transmit power of the UE needs to be increased to reduce theBER. For example, the base station executes step 205.

If BER (i)<BER_(PUCCH) _(—) _(REF), the base station may learn that toreduce network interference, the PUCCH transmit power of the UE needs tobe reduced. For example, the base station executes step 206.

If BER(i)=BER_(PUCCH) _(—) _(REF), the base station may learn that ananti-interference capability and performance of the UE may be maintainedwithout changing the PUCCH transmit power of the UE. For example, thebase station executes step 207.

205. The base station sends δ′_(PUCCH)(i−k_(m)) to the UE, whereδ′_(PUCCH)(i−k_(m))=δ_(PUCCH)(i−k_(m))+ΔSINR_(UE) _(—) _(QCI)(i), whereΔSINR_(UE) _(—) _(QCI)(i) indicates a first signal to interference plusnoise ratio offset used by the UE at the subframe i and is used toincrease the transmit power.

Optionally, ΔSINR_(UE) _(—) _(QCI)(i)=SINR₀ _(—) _(UE) _(—) _(PUCCH)_(—) _(MAX)(i)−SINR₀ _(—) _(NOMINAL) _(—) _(PUCCH). SINR₀ _(—)_(NOMINAL) _(—) _(PUCCH) here may refer to the description about theSINR₀ _(—) _(NOMINAL) _(—) _(PUCCH) in the foregoing embodiment. Forexample, the base station may obtain the SINR₀ _(—) _(NOMINAL) _(—)_(PUCCH) by executing steps 101 to 102 in the foregoing embodiment,which is not repeatedly described here. The ΔSINR_(UE) _(—) _(QCI)(i)may indicate a relative offset between a signal to interference plusnoise ratio that the base station expects the PUCCH, which uses thesecond uplink control information format, to reach in order to ensurethe quality of service of the highest-class service used by the UE, anda signal to interference plus noise ratio that the base station expectsthe PUCCH, which uses a first uplink control information format, toreach in order to ensure quality of service of the lowest-class serviceused by the UE. Therefore, the offset can reflect needs of services ofdifferent classes. Therefore, while increasing the PUCCH transmit powerof the UE, the base station may ensure reliability of signalingtransmission in the case that the PUCCH channel of each UE in the cellunder control of the base station is based on code divisionmultiplexing.

206. The base station sends δ′_(PUCCH)(i−k_(m)) to the UE, whereδ′_(PUCCH)(i−k_(m))=δ_(PUCCH)(i−k_(m))−ΔSINR_(OFFSET)(i), whereΔSINR_(OFFSET)(i) indicates a second signal to interference plus noiseratio offset used by the UE at the subframe i and is used to reduce thetransmit power.

Optionally, the base station sets an initial value of theΔSINR_(OFFSET), and performs adjustment according to an actualcondition, and uses an adjusted ΔSINR_(OFFSET) when executing PUCCHpower control (for example, executing step 206) next time. For example,the initial value of the ΔSINR_(OFFSET) may be 1 dB, and the basestation performs adjustment by using 1 dB as a step. Optionally,adjusting of the ΔSINR_(OFFSET) by the base station may reflect fastincrease and slow decrease, that is, a step used by a value ofΔSINR_(UE) _(—) _(QCI) when the base station increases the transmitpower is greater than a step used by a value of ΔSINR_(OFFSET) when thebase station reduces the transmit power, for example, the former is 2dB, and the latter is 1 dB.

In this step, the base station may preset the ΔSINR_(OFFSET), or mayperform the test estimation under the channel condition so as to obtainthe ΔSINR_(OFFSET). Those skilled in the art may understand that theΔSINR_(OFFSET) obtained by the base station through estimation accordingto different scenarios and/or different channel conditions is different.By adjusting the value of the ΔSINR_(OFFSET), transmit power of acorresponding UE under the base station may be reduced when the PUCCHBER meets a requirement, thereby reducing interference on a neighboringcell while ensuring the performance of the UE.

207. The base station sends δ′_(PUCCH)(i−k_(m)) to the UE, where a valueof δ′_(PUCCH)(i−k_(m)) is the same as a value of δ_(PUCCH)(i−k_(m)).

In this embodiment, because the base station may use a manner of sendingthe δ_(PUCCH)(i−k_(m)) in the prior art to send the δ′_(PUCCH)(i−k_(m)),the base station in this step actually sends the δ_(PUCCH)(i−k_(m))obtained in step 203 to the UE.

Optionally, in any one of steps 205 to 207 in this embodiment, the basestation sends the δ′_(PUCCH)(i−k_(m)) to the UE through a physicaldownlink control channel (Physical Downlink Control Channel, PDCCH).

In this embodiment, the base station first adjusts the obtainedδ_(PUCCH)(i−k_(m)) and then sends the δ′_(PUCCH)(i−k_(m)) obtainedthrough adjustment to the UE. Because the δ′_(PUCCH)(i−k_(m)) is moreaccurate than the δ_(PUCCH)(i−k_(m)) obtained by the base station, theP_(PUCCH)(i) obtained by the UE is more accurate. Therefore, thereliability of signaling transmission can be ensured in the case thatthe PUCCH channel of each UE in the cell under the control of the basestation is based on the code division multiplexing.

When this embodiment is applied in a scenario where the UE keeps online,the UE may perform open loop power control of the PUCCH transmit powerby using the prior art, and perform closed-loop power control of thePUCCH transmit power by using the method provided by this embodiment. Inthe closed-loop power control, the P_(PUCCH)(i) determined by theUE=min{P_(CMAX), P₀ _(—) _(PUCCH)+PL+h(n_(CQI), n_(HARQ))+Δ_(F) _(—)_(PUCCH)(F)+g(i)}. Therefore, the UE determines accurate g(i) accordingto the received accurate δ_(PUCCH), thereby performing accurateclosed-loop power control of the PUCCH transmit power according to theforegoing formula.

Those skilled in the art may understand that the base station can sendthe δ_(PUCCH) for the UE to obtain the g(i) regardless of the FDD systemor the TDD system, thus implementing the closed-loop power control.Therefore, the foregoing embodiment is applicable to both the FDD systemand the TDD system.

Another embodiment of the present invention provides a power controlmethod. In this embodiment, a base station may send a parameter relatedto P_(PUCCH)(i) of an online UE to the UE in a cell under control of thebase station, for example, P₀ _(—) _(NOMINAL) _(—) _(PUCCH), P₀ _(—)_(UE) _(—) _(PUCCH), and δ_(PUCCH) By using the method provided by theforegoing embodiment of the present invention, the base station adjuststhe P₀ _(—) _(NOMINAL) _(—) _(PUCCH) (such as steps 101 to 105 or 106)and δ_(PUCCH) (such as steps 201 to 205 or 206 or 207), so that the P₀_(—) _(NOMINAL) _(—) _(PUCCH) and δ_(PUCCH) sent by the base station tothe UE are more accurate. Therefore, the UE obtains accurate P₀ _(—)_(PUCCH) according to the accurate P₀ _(—) _(NOMINAL) _(—) _(PUCCH), andobtains accurate g(i) according to the accurate δ_(PUCCH), therebymaking the finally obtained P_(PUCCH)(i) more accurate. In thisembodiment, before sending the P₀ _(—) _(NOMINAL) _(—) _(PUCCH) andδ_(PUCCH) to the UE, the base station only needs to respectivelycomplete steps 101 to 105 or 106, and steps 201 to 205 or 206 or 207,where an execution sequence of the foregoing steps does not need to belimited.

Referring to FIG. 3, another embodiment of the present inventionprovides a base station 30. The base station 30 may include a firstobtaining unit 301 and a first sending unit 302. The first obtainingunit 301 is configured to obtain IN_(PUCCH)(i), where the IN_(PUCCH)(i)is average interference noise power of a physical uplink control channel(PUCCH) carried by radio resources that are allocated by the basestation at a subframe i. The first sending unit 302 is configured tosend a parameter P₀ _(—) _(NOMINAL) _(—) _(PUCCH)(i) for power controlat the subframe i, where, if a relative difference between theIN_(PUCCH)(i) obtained by the first obtaining unit 301 and a powerreference value IN_(PUCCH) _(—) _(REF) is greater than a thresholdIN_(TH) _(—) _(PUCCH), a value of the P₀ _(—) _(NOMINAL) _(—)_(PUCCH)(i) is a sum of SINR₀ _(—) _(NOMINAL) _(—) _(PUCCH) andIN_(PUCCH) at the subframe i, where the SINR₀ _(—) _(NOMINAL) _(—)_(PUCCH) may be a first signal to interference plus noise ratio of thePUCCH, where the ratio is obtained by the first obtaining unit 301according to a lowest-class service used by a UE located at a cell edgeand a first uplink control information format; otherwise, the value ofthe P₀ _(—) _(NOMINAL) _(—) _(PUCCH)(i) is the same as a value of aparameter P₀ _(—) _(NOMINAL) _(—) _(PUCCH)(i−1) for the power control ata subframe i−1.

Optionally, the base station 30 further includes: a first processingunit 303, configured to judge whether the relative difference betweenthe IN_(PUCCH)(i) obtained by the first obtaining unit 301 and the powerreference value IN_(PUCCH) _(—) _(REF) is greater than the thresholdIN_(TH) _(—) _(PUCCH), and provides a judging result to the firstsending unit 302. Accordingly, the first sending unit 302 sends the P₀_(—) _(NOMINAL) _(—) _(PUCCH)(i) according to the judging resultprovided by the first processing unit 303.

Optionally, the first uplink control information format is set accordingto a control signaling type carried on the PUCCH, and may be one ofFORMAT 1a, FORMAT 1b, FORMAT 2, FORMAT 2a, and FORMAT 2b.

Optionally, the SINR₀ _(—) _(NOMINAL) _(—) _(PUCCH) is a signal tointerference plus noise ratio that the base station expects the PUCCH,which uses the first uplink control information format, to reach inorder to ensure quality of the lowest-class service used by the UE.

The base station in this embodiment is applied in a scenario where theUE accesses a certain cell under control of the base station, and inthis case, P_(PUCCH)(i) determined by the UE=min{P_(CMAX), P₀ _(—)_(PUCCH)+PL+h(n_(CQI), n_(HARQ))+Δ_(F) _(—) _(PUCCH)(F)}. Therefore, theUE determines accurate P₀ _(—) _(PUCCH) according to the accurate P₀_(—) _(NOMINAL) _(—) _(PUCCH) received from the first sending unit 302and performs accurate open loop power control of PUCCH transmit poweraccording to the foregoing formula.

The base station in this embodiment may be used in the method providedby the embodiment shown in FIG. 1, that is, executes the actionsimplemented by the base station in the method. Reference may also bemade to the description in the method for the parameters and scenarioused by the base station in this embodiment, which are not repeatedlydescribed here. In addition, the base station in the embodiment isapplicable to both an FDD system and a TDD system.

Referring to FIG. 4, another embodiment of the present inventionprovides a base station 40. The base station 40 may include a secondobtaining unit 401 and a second sending unit 402. The second obtainingunit 401 is configured to obtain a bit error rate BER(i) of a physicaluplink control channel (PUCCH) of a user equipment (UE) at a subframe i.The second sending unit 402 is configured to send a transmit powercontrol command δ′_(PUCCH)(i−k_(m)), where a value of m ranges from 0 toM−1, and M is an integer greater than 1. Optionally, a value ofδ′_(PUCCH)(i−k_(m)) is any one of the following:

if the BER(i) obtained by the second obtaining unit 401 is greater thana bit error rate reference value BER_(PUCCH) _(—) _(REF),δ′_(PUCCH)(i−k_(m))=δ_(PUCCH)(i−k_(m))+ΔSINR_(UE) _(—) _(QCI), where theΔSINR_(UE) _(—) _(QCI)(i) is a first signal to interference plus noiseratio offset used by the UE at the subframe i; or

if the BER(i) obtained by the second obtaining unit 401 is smaller thanthe BER_(PUCCH) _(—) _(REF),δ′_(PUCCH)(i−k_(m))=δ_(PUCCH)(i−k_(m))−ΔSINR_(OFFSET), where theΔSINR_(OFFSET)(i) is a second signal to interference plus noise ratiooffset used by the UE at the subframe i; or

if the BER(i) obtained by the second obtaining unit 401 is equal to theBER_(PUCCH) _(—) _(REF), the value of the δ′_(PUCCH)(i−k_(m)) is thesame as a value of the δ_(PUCCH)(i−k_(m)), where the δ_(PUCCH)(i−k_(m))is a transmit power control command obtained by the second obtainingunit 401 at a subframe i−k_(m).

Optionally, ΔSINR_(UE) _(—) _(QCI)(i)=SINR₀ _(—) _(UE) _(—) _(PUCCH)_(—) _(MAX)(i)−SINR_(O) _(—) _(NOMINAL) _(—) _(PUCCH). Reference may bemade to the description about the SINR₀ _(—) _(NOMINAL) _(—) _(PUCCH) inthe embodiment shown in FIG. 3 for the SINR₀ _(—) _(NOMINAL) _(—)_(PUCCH), which is not repeatedly described here. The SINR₀ _(—) _(UE)_(—) _(PUCCH) _(—) _(MAX)(i) is a second signal to interference plusnoise ratio obtained by the second obtaining unit 401 according to ahighest-class service used by the UE at a time i and a second uplinkcontrol information format, and SINR₀ _(—) _(UE) _(—) _(PUCCH) _(—)_(MAX) is a signal to interference plus noise ratio that the basestation expects the PUCCH, which uses the second uplink controlinformation format, to reach in order to ensure quality of service ofthe highest-class service used by the UE.

Optionally, the second obtaining unit 401 is further configured toobtain the highest-class service used by the UE at the time i and thesecond uplink control information format, for example, the secondobtaining unit 401 obtains the foregoing highest-class service andsecond uplink control information format when the UE begins to use thehighest-class service.

The base station in this embodiment is applied in a scenario where theUE keeps online. In this case, the UE may perform open loop powercontrol of PUCCH transmit power by using the prior art, and performclosed-loop power control of the PUCCH transmit power by using themethod provided by this embodiment. In the closed-loop power control,P_(PUCCH)(i) determined by the UE=min{P_(CMAX), P₀ _(—)_(PUCCH)+PL+h(n_(CQI), n_(HARQ))+Δ_(F) _(—) _(PUCCH)(F)+g(i)}.Therefore, the UE determines accurate g(i) according to accurateδ_(PUCCH) sent by the second sending unit 402, thereby performingaccurate closed-loop power control of the PUCCH transmit power accordingto the foregoing formula.

Optionally, the base station 40 further includes: a second processingunit 403, configured to compare the BER(i) obtained by the secondobtaining unit 401 with the bit error reference value BER_(PUCCH) _(—)_(REF), and provide a judging result to the second sending unit 402.Accordingly, the second sending unit 402 sends the δ′_(PUCCH)(i−k_(m))according to the judging result provided by the second processing unit403.

The base station in this embodiment may be used in the method providedby the embodiment shown in FIG. 2, that is, executes the actionsimplemented by the base station in the method. Reference may also bemade to the description in the method for the parameters and scenarioused by the base station in this embodiment, which are not repeatedlydescribed here. In addition, the base station in this embodiment isapplicable to both an FDD system and a TDD system.

Referring to FIG. 5, another embodiment of the present inventionprovides a base station 50, where the base station 50 may include athird obtaining unit 501 and a third sending unit 502. The thirdobtaining unit 501 includes the first obtaining unit 301 in the basestation 30 and the second obtaining unit 401 in the base station 40provided by the foregoing embodiments, and the third sending unit 502includes the first sending unit 302 in the base station 30 and thesecond sending unit 402 in the base station 40 provided by the foregoingembodiments.

Optionally, the base station 50 further includes a third processing unit503. The third processing unit 503 includes the first processing unit303 in the base station 30 and the second processing unit 403 in thebase station 40 provided by the foregoing embodiments.

P_(O) _(—) _(NOMINAL) _(—) _(PUCCH) and δ_(PUCCH) sent by the basestation provided by the embodiment to a UE are more accurate. Therefore,the UE obtains accurate P0_PUCCH according to the accurate P₀ _(—)NOMINAL_PUCCH, and obtains accurate g(i) according to the accurateδ_(PUCCH), thereby making finally obtained PPUCCH(i) more accurate. Thebase station in this embodiment is applicable to both an FDD system anda TDD system.

Persons of ordinary skill in the art may understand that all or part ofthe steps of the methods according to the foregoing embodiments may beimplemented by a program instructing relevant hardware. The program maybe stored in a computer readable storage medium, where the medium mayinclude: a ROM, a RAM, a magnetic disk, a compact disk, and so on.

The foregoing is a detailed description of a power control method of anLTE PUCCH and a base station provided by the embodiments of the presentinvention. The principle and implementation manner of the presentinvention are described with reference to specific embodiments, and theforegoing embodiments are only intended to help understand the methodsand a core idea of the present invention. Meanwhile, with respect to thespecific implementation manner and the application scope of the presentinvention, modifications may be made by persons of ordinary skill in theart according to the idea of the present invention. To sum up, thecontent of the specification shall not be construed as a limitation onthe present invention.

What is claimed is:
 1. A power control method comprising: obtaining, bya base station, a bit error rate BER(i) of a physical uplink controlchannel (PUCCH) of a user equipment (UE) at a subframe i; and sending,by the base station, a transmit power control commandδ′_(PUCCH)(i−k_(m)), wherein a value of m ranges from 0 to M−1, M is aninteger greater than 1, and a value of the δ′_(PUCCH)(i−k_(m)) is anyone of the following: if the BER(i) is greater than a bit error ratereference value BER_(PUCCH) _(—) _(REF),δ′_(PUCCH)(i−k_(m))=δ_(PUCCH)(i−k_(m))+ΔSINR_(UE) _(—) _(QCI)(i),wherein the ΔSINR_(UE) _(—) _(QCI)(i) is a first signal to interferenceplus noise ratio offset used by the UE at the subframe i; if the BER(i)is smaller than the BER_(PUCCH) _(—) _(REF),δ′_(PUCCH)(i−k_(m))=δ_(PUCCH)(i−k_(m))−ΔSINR_(OFFSET)(i), wherein theΔSINR_(OFFSET)(i) is a second signal to interference plus noise ratiooffset used by the UE at the subframe i; and if the BER(i) is equal tothe BER_(PUCCH) _(—) _(REF), the value of the δ′_(PUCCH)(i−k_(m)) is thesame as a value of the δ_(PUCCH)(i−k_(m)), wherein theδ_(PUCCH)(i−k_(m)) is a transmit power control command obtained by thebase station at a subframe i−k_(m).
 2. The method according to claim 1,wherein: a value of the ΔSINR_(UE) _(—) _(QCI)(i) is a differencebetween SINR₀ _(—) _(UE) _(—) _(PUCCH) _(—) _(MAX)(i) and SINR_(O) _(—)_(NOMINAL) _(—) _(PUCCH); wherein the SINR₀ _(—) _(UE) _(—) _(PUCCH)_(—) _(MAX)(i) is a second signal to interference plus noise ratioobtained by the base station according to a highest-class service usedby the UE at the subframe i and a second uplink control informationformat, and the SINR₀ _(—) _(NOMINAL) _(—) _(PUCCH) is a signal tointerference plus noise ratio that the base station expects the PUCCH,which uses a first uplink control information format, to reach in orderto ensure quality of the lowest-class service used by the UE.
 3. Themethod according to claim 2, further comprising: obtaining, by the basestation, the highest-class service used by the UE and the second uplinkcontrol information format when the UE begins to use the highest-classservice.
 4. The method according to claim 2, wherein the SINR₀ _(—)_(UE) _(—) _(PUCCH) _(—) _(MAX) is a signal to interference plus noiseratio that the base station expects the PUCCH, which uses the seconduplink control information format, to reach in order to ensure qualityof service of the highest-class service used by the UE.
 5. The methodaccording to claim 2, further comprising: obtaining, by the basestation, the SINR₀ _(—) _(NOMINAL) _(—) _(PUCCH) according to alowest-class service used by the UE and the first uplink controlinformation format, wherein the SINR₀ _(—) _(NOMINAL) _(—) _(PUCCH) iscorresponding to the lowest-class service used by the UE and satisfies ademodulation threshold requirement for demodulating feedback informationcarried on the PUCCH of the first uplink control information format. 6.The method according to claim 2, wherein at least one of the firstuplink control information format and the second uplink controlinformation format is any one of the following formats: format 1A,format 1B, format 2, format 2A, and format 2B.
 7. The method accordingto claim 1, wherein the δ′_(PUCCH)(i−k_(m)) is used to obtain acalibration value of inner loop power control, g(i), wherein the g(i) isused to compensate an error which is set for initial power of an openloop power control of the UE.
 8. The method according to claim 1,wherein the UE is an online UE located at an edge of a cell undercontrol of the base station.
 9. A base station comprising: a secondobtaining unit configured to obtain a bit error rate BER(i) of aphysical uplink control channel (PUCCH) of a user equipment (UE) at asubframe i; and a second sending unit configured to send a transmitpower control command δ′_(PUCCH)(i−k_(m)), wherein a value of m rangesfrom 0 to M−1, M is an integer greater than 1, and a value of theδ′_(PUCCH)(i−k_(m)) is any one of the following: if the BER(i) isgreater than a bit error rate reference value BER_(PUCCH) _(—) _(REF),δ′_(PUCCH)(i−k_(m))=δ_(PUCCH)(i−k_(m))+ΔSINR_(UE) _(—) _(QCI)(i),wherein the ΔSINR_(UE) _(—) _(QCI)(i) is a first signal to interferenceplus noise ratio offset used by the UE at the subframe i; if the BER(i)is smaller than the BER_(PUCCH) _(—) _(REF),δ′_(PUCCH)(i−k_(m))=δ_(PUCCH)(i−k_(m))−ΔSINR_(OFFSET)(i), wherein theΔSINR_(OFFSET)(i) is a second signal to interference plus noise ratiooffset used by the UE at the subframe i; or if the BER(i) is equal tothe BER_(PUCCH) _(—) _(REF), the value of the δ′_(PUCCH)(i−k_(m)) is thesame as a value of the δ_(PUCCH)(i−k_(m)), wherein the δ_(PUCCH)(i−k_(m)) is a transmit power control command obtained by the secondobtaining unit at a subframe i−k_(m).
 10. The base station according toclaim 9, wherein a value of the ΔSINR_(UE) _(—) _(QCI)(i) is adifference between SINR₀ _(—) _(UE) _(—) _(PUCCH) _(—) _(MAX)(i) and theSINR₀ _(—) _(NOMINAL) _(—) _(PUCCH); wherein the SINR₀ _(—) _(UE) _(—)_(PUCCH) _(—) _(MAX)(i) is a second signal to interference plus noiseratio obtained by the second obtaining unit according to a highest-classservice used by the UE at the subframe i and a second uplink controlinformation format, and the SINR₀ _(—) _(NOMINAL) _(—) _(PUCCH) is asignal to interference plus noise ratio that the base station expectsthe PUCCH, which uses a first uplink control information format, toreach in order to ensure quality of the lowest-class service used by theUE.
 11. The base station according to claim 10, wherein the secondobtaining unit is further configured to: obtain the highest-classservice used by the UE and the second uplink control information formatwhen the UE begins to use the highest-class service.
 12. The basestation according to claim 10, wherein the SINR₀ _(—) _(UE) _(—)_(PUCCH) _(—) _(MAX) is a signal to interference plus noise ratio thatthe base station expects the PUCCH, which uses the second uplink controlinformation format, to reach in order to ensure quality of service ofthe highest-class service used by the UE.
 13. The base station accordingto claim 10, further comprising: obtaining, by the base station, theSINR₀ _(—) _(NOMINAL) _(—) _(PUCCH) according to a lowest-class serviceused by the UE and the first uplink control information format, whereinthe SINR₀ _(—) _(NOMINAL) _(—) _(PUCCH) is corresponding to thelowest-class service used by the UE and satisfies a demodulationthreshold requirement for demodulating feedback information carried onthe PUCCH of the first uplink control information format.
 14. The basestation according to claim 10, wherein at least one of the first uplinkcontrol information format and the second uplink control informationformat is any one of the following formats: format 1A, format 1B, format2, format 2A, and format 2B.
 15. The base station according to claim 9,wherein the δ′_(PUCCH)(i−k_(m)) is used to obtain a calibration value ofinner loop power control, g(i), wherein the g(i) is used to compensatean error which is set for initial power of an open loop power control ofthe UE.
 16. The base station according to claim 9, wherein the UE is anonline UE located at an edge of a cell under control of the basestation.
 17. The base station according to claim 9, wherein the basestation is configured to work in at least one of: a frequency divisionduplex (FDD) system, and a time division duplex (TDD) system.